1. Field of the Invention
This invention relates to a endoscopic resecting system which removes methyl-methacrylate (bone cement) or some other grouting agent and ossues tissue from the human body femoral canal during revision hip surgery to treat arthritis of the hip joint.
2. Description of Prior Art
Normal method for treatment of severe arthritis of the hip involves performing an internal amputation of the proximal end of the femur, and its replacement with an appropriately shaped metallic device. A spacer or grouting agent, methylmethacrylate, called bone cement, is used to seat and secure the metal implant into the femur. As the patient walks or runs on the implant after the primary procedure, the bone cement, being brittle, begins to crack and as a result the implant loosens, causing the original arthritic pain to return. Eventually, the metallic femoral implant must be replaced. Bone cement, so effective during the initial procedure, now becomes a major problem because it must be meticulously removed, lest it become a nitus for failure of the replacement prosthesis.
Pneumatically operated devices and manual instruments are currently used to remove cement and completely clean out the femoral canal. Pneumatic motors are difficult to operate, require heavy hoses to connect motor to source of gas, can require tanks of air to be placed in a surgical environment that is keep very clean by use of hepa-filters, and vent unsterile air into this same clean environment. In performing a patent search, specific patents which describe this pneumatic motor technology have not been identified. Use of manual instruments is performed cautiously and as a result extends operating time and general anesthesia time. Manual instruments designed for this surgical procedure are not described or claimed in patents currently in force. Other forms of energy are being employed experimentally to accomplish the same.
With an aging population, treatment of hip arthritis by hip replacement will be more common. Likewise, revision of the first implant operation will be more common. Therefore, there is significant need for a device which will make this surgical procedure more effective.
The problem confronting the orthopaedic surgeon performing this procedure is that the surgeon must work at the end of a six to eight inch deep, dark hole in the femur that has an opening about one inch across. Into this hole are introduced high speed, greater than 50,000 rpms pneumatically or hand operated sharp cutting tool which occupy half of the opening. Then the surgeon must look past these impediments to visualize down to the end of this dark hole. As a result, it is difficult to differentiate between cement which must be removed and the underlying cortical bone, which must not be removed.
Given these conditions, sharp tools, necessary to remove cement, are not effectively controlled with the result that undesired holes or perforations are cut in the femur and are common. When perforation occurs, a 6-8 inch extension of the surgical wound, distally down the shaft of the femur is required, along with debridement of the perforation, and usually bone graft to correct the defect. This results in considerably greater pain, suffering, and morbidity, about an hour additional general anesthesia time, and more cost. Sometimes the final condition which results is osteomyelitis, a whole new form of orthopaedic malady, with significantly higher morbidity and complications.
Although a fluoroscopic image intensifier can be used to identify impending perforation out of the shaft of the femur, more likely it will confirm perforation rather than prevent it. Use of a flouroscope dictates exposure to cancer causing x-rays or related use of heavy lead aprons by operating room persons, both of which add to the difficulty of this already difficult procedure.
Related prior art involves small diameter, optical medical telescopes which have been used for orthopaedic arthroscopy for several years, and other surgical procedures for decades. Arthroscopes have a shape and size that make them beneficial in performing the arthroscopic technique, but not effective for performing revision hip surgery.
Additional related prior art is fiber optic light illuminators that are used for medical, endoscopic surgical procedures in general and for orthopaedic arthroscopy in particular. These light sources do not provide the light intensity to properly illuminate the femoral canal, and produce clear images with the medical video camera system that is used in conjunction with the femoral canal endoscope.
Additional related prior art is a peristaltic pump used to instill fluid, usually normal salline, into a body cavity to expand its volume, and provide a clear liquid medium to view the body cavity using a generic type of endoscope. This instilled fluid may be removed from the body cavity either through the endoscope or through a separate outflow conduit, usually by applying active suction to the conduit and conecting PVC tubing, the suction being generated by some aspirating external pump. Precise control of rate of inflow is not achieved with prior art instilling pumps, and coordination of volume of inflow to volume of aspiration, through electronic controls is not characteristic of these forms of prior art.
Related prior art are machines which function independently including light source illuminators, and peristaltic pumps, used for surgical procedures other than indicated in this patent application.
Additional related prior art is a high speed, pneumatically powered motor which drives a sharp burr that actually abrades away the cement. A pneumatic motor requires difficult to use compressed air tanks. Prior art devices vent unsterile air into an environment that is attempted to be kept meticulously clean by circulation of this air through hepafilters.
U.S. Pat. No. 4,132,227, entitled Urological Endoscope Particularly Resectoscope, issued to Wolfgang Ibe on Jan. 2, 1979, teaches a hollow cylinder sheath, a viewing device, an illuminating device, a resecting device and an outflow tube The hollow cylinder sheath has a proximal end and a distal end. The viewing device is an endoscopic arrangement of optical elements. The illuminating device is a cooperating arrangement of fiber optics which is optically coupled to a light source. The viewing device and the illuminating device are located in the sheath extending from the distal end back to the proximal end. The outflow tube is slidable onto the sheath to surround the sheath and form together with the sheath an intermediate return-flow space between the outer wall of the sheath and the inner wall of the outflow tube, with the outflow tube when in position slid over the sheath tightly surrounding the distal end portion of the sheath. The resecting device is an electrode loop which is electrically coupled to an electromagnetic energy source. Clear rinsing water is introduced into the proximal end of the sheath. Turbid water is removed from the proximal end of the intermediate space. The outflow tube is provided with apertures at the distal end thereof for the flow of clear rinsing water out of the distal end of the sheath and around the end of the endoscope and then through the apertures into the intermediate space. U.S. Pat. No. 4,607,621, entitled Endoscopic Apparatus, issued to Robert C. Wheeler on Aug. 26, 1986, teaches an insertion tube, an electrosurgical generator and an electrode loop which is electrically coupled to the electrosurgical generator.
U S. Pat. No. 4,756,309, entitled Endoscope for Removal of Tissue, issued to Hans-Ernst Sachse on July 12, 1988, teaches an endoscope which resects tissue inside body cavities and which includes a hollow outer tube, a rotating shaft and a flushing duct. The shaft carries a grinding or milling head which allows precise removal of scar tissue or other fairly firm tissue under endoscopic control without leaving irregular or thermally damaged wound sites. The endoscope also includes a tube for a lens system and cold light guide and an eyepiece.
U.S. Pat. No. 4,844,062, entitled Rotating Fiberoptic Laser Catheter Assembly with Eccentric Lumen, issued to Lisa D. Wells on July 4, 1989, teaches a catheter assembly which includes a catheter and an optical fiber. The catheter defines a first eccentric lumen which encompasses the center of the catheter and a second lumen. The optical fiber runs through the first eccentric lumen and has a distal end which is eccentric to and encompasses the center of the catheter. U.S. Pat. No. 4,865,018, entitled Control Apparatus for Endoscopes, issued to Masahide Kanno, Katasuyaki Saito and Akihiko Miyazaki on Sept. 12, 1989, teaches a control apparatus which controls a plurality of functions of an endosocpe. U.S. Pat. No. 4,550,716, entitled Liquid Supplying Device for Endoscope, issued to Kunio Kinoshita on Nov. 5, 1985, teaches a liquid supplying device which includes a housing with a connecting portion to which a connector of an endoscope is connected. The liquid supplying device also includes a lamp, an air pump, and a liquid supply tank.
U.S. Pat. No. 3,618,611, entitled Vacuum Rotary Dissector, issued to Julius C. Urban on Nov. 9, 1971, teaches a vacuum rotary dissector which includes a support, an outer tubular member, an inner tubular member and a motor. The outer tubular member extends from the support and has a closed generally hemispherical distal end and a first laterally directed opening adjacent to its distal end extending axially along the outer tubular member and partially along the closed generally hemispherical distal end. The inner tubular member is rotatably mounted in the outer tubular member and has a complementary generally hemisperical distal end frictionally bearing on an inner complementary surface of the closed generally hemispherical distal end of the outer tubular member. The inner tubular member has a second laterally directed opening coextensive with the first laterally directed opening defining generally axially extending cutting edges coincident with the inner surface of the outer tubular member. The motor continuously rotates the inner tubular member relatively to the support and the outer tubular member.
U.S. Pat. No. 4,598,710, entitled Surgical Instrument and Method of Making Same, issued to Larry K. Kleinberg and Donald S. Evans on July 8, 1986, teaches an arthroscopy shaver which includes a pair of co-axially assembled tubes. The tubes have their distal walls in bearing relationship and with registrable openings extending through such distal and annular walls correspondingly joined to their respective distal walls. U.S. Pat. No. 4,203,444, entitled Surgical Instrument Suitable for Closed Surgery Such as of the Knee, issued to Leonard J. Bonnell, Edward H. McHugh, Douglas D. Sjostrom and Lanny L. Johnson on May 20, 1980, also teaches an arthroscopy shaver.